Air outlet louver assemblies are commonly used in automobile ventilation systems to permit a user to adjust the direction and volume of airflow into a passenger compartment of an automobile. Louver assemblies generally include one or two sets of directional vanes that are pivotally disposed within a housing and at least one control handle to adjust the position of the vanes within the housing. In addition, many louver assemblies include a damper door that pivots within the housing to adjust the volume of airflow through the housing.
To improve the ease with which a user can adjust the vanes, many louver assemblies include a positioning device to provide intermittent frictional resistance to movement of the vanes and create spaced rest locations for the vanes. In other words, two-way ratcheting control is provided to improve the "feel" of a control handle during adjustment of the vanes. The ratchet device thus makes it easier for a user to adjust the vanes in discrete increments and also maintains the vanes in their selected position in spite of any bumps or jarring motion received by the automobile.
For example, U.S. Pat. No. 3,861,281 to Godwin illustrates an outlet louver of this type. The louver includes a plurality of directional vanes pivotally disposed within a first housing for adjusting the horizontal direction of airflow when moved. In addition, the first housing pivots within a second housing to adjust the vertical direction of airflow. The first housing includes a plurality of ridges along an outer surface thereof in sliding frictional contact with an arm extending from the second housing. In this manner, ratcheting control is provided for the pivotal movement of the first housing within the second housing.
However, in Godwin U.S. Pat. No. 3,861,281 the first housing extends outwardly from the second housing upon pivotal movement with respect to the second housing. In addition to providing a potential hazard to passengers, extension of the first housing outside of the second housing disrupts the aesthetic contour of the dashboard. To avoid these problems, modern outlet louver assemblies utilize a single housing including two sets of directional vanes disposed for pivotal movement within the housing. This eliminates the need for pivotal motion of the first housing because the two sets of directional vanes provide complete directional control of the airflow. However, ratcheting contact between a first and second housing is precluded with only one housing.
To solve this problem, ratcheting systems for single-housing outlet louvers have been designed. U.S. Pat. No. 3,735,691 to Gofton et al. illustrates an outlet louver of this type. The louver includes a housing 12 and a plurality of vanes 36 pivotally disposed therein. A gang bar 48 is attached to each of the vanes 36 for joining the vanes in coupled pivotal motion within the housing 12. Ratchet teeth 52 on the gang bar 48 interact with grooves 26 on the housing to provide ratcheting control of the vanes 36. However, the Gofton U.S. Pat. No. 3,735,691 ratchet system will not work in systems without a gang bar 48, such as those with only one directional vane. In addition, the gang bar 48 must be located immediately adjacent the housing 12, reducing design options for the outlet louver.